It looks like you have two different bikes here...
One that got ridden, and one that didn't.
It may be that the shadow had an owner that was a wkend rider, or, it might have been sitting. No way to really know.
Considering they are the same age, the Vulcan might be the better by even with the mileage because its not good for a bike to sit. You tend to have more problems with bikes if they weren't addressed for long sits between rides.
Bikes that have a few miles on them generally, tend to be more reliable.
19,000 miles for a 4 year old bike is not bad. That about 5,000 miles per year.
Geez...I put that on my bike in 4 short months!
No matter which bike, try to get maint/service records for them.
I would shoot for the Vulcan first and try to get him down on the price. Because of the mileage, you have some negotiating room.
To give you a frame of reference, I purchased a 2002 Vulan 750 last August (NY/NJ area). It had 5000 miles on the odometer. The guy was a wkend rider and could no longer ride do to some back problems. The bike had a windshield, driving lights, new maint free battery. I paid $3500. I have no regrets...bike has been great.
This too, is my first motorcycle.... be safe and enjoy!